Safety valve interlock



5 R. A. SHIELDS 2,538,335

SAFETY VALVE INTERLOCK Filed March 7, 1947 2 Sheets-Sheet l INVENTOR 16, 1951 R. A. SHIELDS SAFETY VALVE INTERLOCK 2 Sheets-Sheet 2 Filed March 7, 1947 INVENTOR Wmm Patented Jan. 16, 1951 SAFETY VALVE INTERLOCK Robert A. Shields. Bloomsburg, Pa., assignor to American Car and Foundry Company, New York,'N. Y., a corporation of New Jersey Application March 7, 1947, Serial No. 732,979

12 Claims.

This invention relates to safety valves in general and in particular to multiple safety valves for use with inflammable or corrosive gases in storage or transit.

In the storage of highly inflammable or corrosive gases and liquids it is necessary that the containers be provided with safety valves, each of sufficient capacity as to fully protect the container. These safety valves may now be mounted with a three-wayvalve so arranged as to permit removal of either one of the valves, but since this three-way valve is exterior of the container there is no guarantee that careless workmen cannot remove all of the safety valves by merely removing one and then plugging the opening and removing the other. Likewise, in cases of sabotage the safety valve can be easily removed and the contents of the container readily discharged. It

' is an object, therefore, of the present invention to provide safety valves, the removal of which will not permit discharge of the contents of the container.

A further object of the invention is the provision of two or more safety valves, only one of which can be removed at any one time.

A still further object of the invention is the provision of two or more safety valves so arranged that the removal of one looks all of the remaining valves against removal.

A yet further object of the invention is the provision of two or more safety valves for a container and having interlocks with all controls therefor located within the container and inaccessible from the exterior.

These and other objects of the invention will be apparent to persons skilled in the art from a study of the following decription and accompanying drawings, in which Fig. l is a sectional view taken through the container and safety valves;

Fig. 2 is a sectional view taken substantially on line 2-2 of Fig. 1 with certain parts broken away to better disclose the construction, and

Fig. 3 is a sectional view taken substantially on line 3-3 of Fig. l and showing in detail the interlock cylinders. I

Referring now to the drawings in detail it will be seen thatthe container walls 4 have welded therein tubes "or sleeves 6 finished internally at the lower end as at 8 and at th upper end as at I 0. The lower-finished surface 8 is adapted to be engaged by a resilient packing ring l2 carried by a stop valve .14. This stop valve is provided with a metallic seat l6 adapted to engage a corresponding seat on tube or sleeve 6. Movement of the stop valve is guided by retaining bolts [8 and constantly urged toward a seated position on tube 6 by springs 20. The upper finished surface ll] of the tube or sleeve is adapted to engage a resilient packing ring 22"carried by safety valve body 24 clamped in position by means of bolts .26 and a ring 28 into which is fastened an exhaust stack 30. The bolts 26 are engaged in a collar 32 welded or otherwise secured to the upper or outer end of the tube or sleeve 6. The safety valve body has attached thereto an extension 34 of such a length as to retain thestop valve I4 off of its seat when the safety valve is clamped in position as shown in the right hand portion of Fig. 1. The safety valve is'held on its seat by means of a spring 35 acting on the body and valve stem 38. Sealing between the safety valve and body is accomplished by means of a metallic seat and resilient seal arrangement 40, more fully described in application 720,072 filed January 3, 1947. The interaction of the safety valve and the stop valve is more fully explained in application 729,260 filed Februaiyl8, 1947. It is believed sufficient, however, to state that while the safety valve assembly is being removed, as

indicated in the left half of*Fig. 1, pressure trapped below the resilient ring 22 will be vented through vent 42 as soon as the resilient seal has passed above the lower edge of this vent.

In order to interlock the safety valves lock 7 56 is mounted within the lock cylinder. The piston portion 52 is grooved to receive a resilient packing member 58 while the short rod portion 56 is grooved to receive a resilient seal member 69. The long piston rod portion 54 is grooved to receive a resilient sealing ring 62 adapted to engage and seal with a filler member 64 welded or otherwise secured in the open end of the lock cylinder 44 or 45. Outwardly of the sealing ring 62 the rod-54 is provided with a locking portion 66 adapted to engage in a hole or opening 68 formed in the extension 34 of'i 'the safety valve assembly. Sealing rings and 62 and accordthrough which permits interchange of gas between the ends of the piston rods. The chamber between packing ring 58 and the head of the lock cylinder is connected to the interior of the container 4 by means of a passage 12, while the chamber to the opposite side of the sealing ring 58 is vented to the exterior of the lock cylinder through a nipple connection 14. Nipple 54 of lock cylinder 34 is connected by piping I6 and union 18 to the sleeve or tube 6 of the adjacent valve assembly. Nipple 14 of lock cylinder 46 is connected by piping 80 and union 82 to the tube or sleeve 6 carrying the lock cylinder 44. It is obvious that if more than two safety valve assemblies are used the pipes 16 and 80 will have branches connected to the sleeves and lock cylinders of the added valves.

When the safety valves are in normal operation they will be in the position shown to the right of Fig. 1, that is, with the extension 34 holding the stop valve it off of its seat. When,however, it is desirable to remove one of the safety valves it will be lifted to the position shown-to'the left of Fig. l and as soon as seal ring 22 has passed vent 42 the pressure within the sleeve 6 will be vented to atmosphere but the contents of the container can not escape due to the seating of the stop valve M prior to the venting of the sleeve. As soon as the sleeve at the left of Fig. 1 has been vented to atmosphere, pipes 36 and the chamber surrounding piston rod 54 of lock cylinder 46 will be likewise vented to atmosphere. The pressure within the container acting through passage I2 of lock cylinder #55 will push piston 52 to the right forcing the lock proiect-ion 65 into the looking hole 63 of extension 3e. Due to the fact that pipe it is at container pressure and also the passage i2 of lock cylinder 44, the lock piston of cylinder it will remain in the position as shown to the left of Fig. 1. In other words, the piston 52 is balanced on both sides by container pressure, while the piston rod is balanced by atmospheric pressure acting at both ends due to the boring of hole Hi through the rod. In order to insure that the balanced locking pistons remain in the inner end of their bores until unbalanced by unbalanced pressures, springs 99 are inserted in each lock cylinder and these springs should be as light as po sible, that is, of just suflicient strength as to overcome the friction of the parts.

While the valve arrangement and interlocks have been described more or less in detail with specific reference to the use of two safety valves and lock cylinders, it is obvious that more assemblies may be connected and that various modifications may be made without departing from the scope of the following claims defining my invention.

What is claimed is:

l. A multiple valve arrangement for pressure containers comprising, a plurality of sleeves projecting into and secured to the container, removable valve structures closing the outer ends of said sleeves, stop valves secured to the inner end of said sleeves and adapted to close the inner end of the same upon removal of the removable valve structure, and means secured to said sleeves and engageable with said removable valve structures, said means being operable by pressure with.- in the container and so constructed and arranged as to prevent removal of more than'one of said removable valve structures when said container is under pressure.

2. A multiple valve arrangement for .pressure containers comprising, a plurality ofisleeves projecting into and secured to the container, removable valve structures closing the outer ends of said sleeves, stop valves secured to the inner end of said sleeves and adapted to close the inner end of the same upon removal or" the removable valve structure, and means secured to said sleeves and engageable with said removable valve structures intermediate the ends thereof, said means being located wholly within the container and operable by pressure within the container and so constructed and arranged as to prevent removal of more than one of said removable valve structures when said container is under pressure.

3. A multiple valve arrangement for a pressure container comprising, a plurality of openings into the container, each opening adapted to be closed by a normally closed removable valve member and a normally open stop valve member that closes upon removal of the removable valve member, and means so constructed and arranged as to prevent removal of more than one removable valve member when the container is under pressure.

4. A multiple valve arrangement for a pressure container comprising, a plurality of openings into the container, each opening adapted to be closed by a normally closed removable valve member and a normally open stop valve member that closes upon removal of the removable valve memher, and means so constructed and arranged as to prevent removal of more than one removable valve member when the container is under pressure. means being located wholly within the container and inaccessible from the exterior of the container.

5. A multiple valve arrangement for a pressure'container comprising, a plurality of openings into the container, each opening adapted to be closed by a normally closed safety valve and a normally open stop valve which closes upon removal of the safety valve, and means so constructed and arranged as to prevent removal of more than one safety valve when the container is under pressure.

6. A multiple valve arrangement for a pressure container comprising, a plurality of opening nto the container, each opening adapted to be closed by a normally closed safety valve and a normally open stop valve which closes upon removal of the safety valve, and means so constructed and arranged as to prevent removal of more than one safe y valve when the container is under pressure, said means comprising pressure operated means located wholly within the container.

7. A multiple valve system for pressure containers comprising, a plurality .f sleeves projecting into and secured to the container, a safety valve assembly closing the outer end of each of said sleeves. a projection extending inwardly from each safety valve assembly to sub tantially the inner end'of each sleeve, a stop valve secured to the inner end of each of said sleeves and normally held open by the safety valve projection adapted to close the inner end of the sleeve upon removal of the safety valve, lock means carried by each sleeve and movable by pressure Within the container into engagement with said safety valve projection to prevent removal of but one safety valve when said container is under pressure.

8. A multiple valve system for pressure containers comprising, a plurality of sleevesprojecting into and secured to the container, a safety valve assembly closing the outer end of each of said sleeves, a projection extending inwardly the inner end of each sleeve, a stop valve secured to the inner end of each of said sleeves and normally held open by the safety valve projection but adapted to close the inner end of the sleeve upon removal of the safety valve, lock cylinders connected to each of said sleeves, pistons mounted in each of said lock cylinders and having one end adapted to move to locked position in engagement with the adjacent safety valve projection to function as a lock therefor, chambers in the lock cylinders on either side of the pistons, passageways connecting the chambers on one side of the pistons to the interior of the pressure container, and means providing passageways connecting each chamber on the other side of the pistons to the interior of the remaining sleeves remote from the lock cylinder chamber to which said means is connected, whereby upon removal of any safety valve portions of said means are vented to atmosphere and all pistons, except that one adjacent the safety valve removed, are moved to locked position by pressure within the container.

9. A multiple valve system for pressure containers comprising, a plurality of sleeves projecting into and secured to the container, a safety valve assembly closing the outer end of each of said sleeves, a projection extending inwardly from each safety valve assembly to substantially the inner end of each sleeve, a stop valve secured to the inner end of each of said sleeves and normally held open by the safety valve projection but adapted to close the inner end of the sleeve upon removal of the safety valve, lock cylinders connected to each of said sleeves, a conduit connecting one end of each of said lock cylinders to n projection upon venting of said conduit by removal of one of said safety valves.

10. A multiple valve system for pressure conbut adapted to close the inner end of the sleeve upon removal of the safety valve, lock cylinders connected to each of said sleeves, a conduit connecting the inner end of each of said lock cylindersto the interior of the remaining sleeves,

a pas'sagewayconnecting the outer end of each lock cylinder to the container interior, and a pressure balanced piston mounted in each of said lock cylinders and movable under pressure within the container to lock the adjacent "safety valve projection upon an unbalance of pressure caused by venting said conduit by removal of one of said safety valves, said piston being normally held by resilient means in a retracted unlocked position.

11. A multiple valve system for pressure containers comprising, a pair of sleeves projecting into the container, a pair of safety valves with one mounted in the outer end of each sleeve, a pair of stop valves with one mounted on the inner end of said sleeve and adapted to close the inner end of the same upon removal of the adjacent safety valve, a pair of lock means with one secured to each sleeve and having a part operable to engage a part of the adjacent safety valve, and conduit means connecting the lock means of one sleeve to the other sleeve whereby low pressure tainers comprising, a plurality of sleeves projecteach safety valve assembly to substantially the 5 inner end of each sleeve, a stop valve secured to the inner end of each of said sleeves and nor mally held open by the safety valve projection conditions within said other sleeve will cause locking operation of the lock means part of said one sleeve.

12. A. pressure balanced means comprising a cylinder, a piston rod slidable within said cylinder, one end of said piston rod being adapted to function as a lock, an axial opening through said piston rod whereby the ends thereof are pressure balanced at all times, a piston on said rod intermediate its ends and providing chambers on either side thereof and which may be subjected to unbalanced pressures, and resilient annular seal means of circular cross-section sealing the space between the piston rod ends and cylinder and between said piston and cylinder.

ROBERT A. SHIELDS.

REFERENCES CITED The following references are-of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,226,175 Bibleheiser May 15, 1917 1,281,017 Jacobus Oct. 8, 1918 1,764,521, Mullaney June 17, 1930 

